Season the chicken breast evenly with sea salt, black pepper, and dried oregano on both sides.
Heat avocado oil in a large skillet over medium-high heat until shimmering.
Place the chicken in the skillet and sear for 6 to 7 minutes per side, or until the internal temperature reaches 165°F.
Remove the chicken from the pan and let it rest on a cutting board for 5 minutes to keep it juicy.
While the chicken rests, chop the cucumber into bite-sized pieces, halve the cherry tomatoes, and thinly slice the red onion.
In a small jar or bowl, whisk together the juice of the half lemon, apple cider vinegar, dijon mustard, and extra virgin olive oil until emulsified.
Toss the mixed baby greens, cucumber, tomatoes, and onion in a large bowl with half of the prepared dressing.
Slice the chicken breast into thin strips, place them on top of the salad, sprinkle with hemp seeds, and drizzle with the remaining dressing.